主键并非是一个字段,也可以是多个字段。

SQLSERVER,ORACLE都可以设定多个字段合并为主键。

USE [test]GO/****** Object:  Table [dbo].[test3]    Script Date: 12/08/2012 14:19:29 ******/SET ANSI_NULLS ONGOSET QUOTED_IDENTIFIER ONGOCREATE TABLE [dbo].[test3]([id] [int] NOT NULL,[name] [nchar](10) NOT NULL,[gender] [nchar](10) NULL, CONSTRAINT [PK_test3] PRIMARY KEY CLUSTERED ([id] ASC,[name] ASC)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]) ON [PRIMARY]GO